A scanning electron microscope (SEM) is used to generate high-resolution images of objects and to show spatial variations. A SEM uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens. In applications, data are collected over a selected area of the surface of the sample, and a two-dimensional image is generated that displays spatial variations.
While a SEM is useful for a variety of applications, one application in which it is used is with magnetic storage systems to qualitatively and subjectively assess head-media interactions. Magnetic storage systems are utilized in a wide variety of devices in both stationary and mobile computing environments. Magnetic storage systems include hard disk drives (HDD), and solid state hybrid drives (SSHD) that combine features of a solid-state drive (SSD) and a hard disk drive (HDD). Examples of devices that incorporate magnetic storage systems include desktop computers, portable notebook computers, portable hard disk drives, servers, network attached storage, digital versatile disc (DVD) players, high definition television receivers, vehicle control systems, cellular or mobile telephones, television set top boxes, digital cameras, digital video cameras, video game consoles, and portable media players.
Hard disk drive performance demands and design needs have intensified. A hard disk drive typically includes a read head and a write head, generally a magnetic transducer which can sense and change magnetic fields stored on disks. The current demand for larger capacity in a smaller dimension is linked to the demand for ever increasing storage track density. The seek time is the time it takes the head assembly to travel to a disk track where data will be read or written. The time to access data can be improved by reducing seek time, which affects HDD performance. Reduced seek time and very close spacing between the heads and the disk surface make HDDs vulnerable to damage caused by head-media contact, which may cause data loss. While head-media contact can result in immediate head and media failure or data loss, repeated head-media contact can result in eventual head and media degradation, including diamond-like carbon (DLC) wear at the air bearing surface, depletion of media surface lubrication, and scratches to media surface, which can also result in head and media failure or data loss.